UNIVERSITY    OF   CALIFORNIA       AGRICULTURAL    EXPERIMENT    STATION 
COLLEGE    OF    AGRICULTURE  benj.  ide  wheeler,  president 

THOMAS      FORSYTH    HUNT.    Dean  and  Director 

BERKELEY 


CIRCULAR  No.  105 

August,    1913 


ANALYSES  OF  INSECTICIDES  FOR  USERS 


BY 

GEORGE  P.  GRAY 

The  California  Insecticide  Law*  provides  that  "the  .  .  .  Directory 
of  the  agricultural  experiment  station  of  the  University  of  California 
shall,  upon  the  receipt  of  a  sample  of  insecticide,  accompanied  with 
a  nominal  fee  of  one  dollar  furnish  to  the  USER  of  said  commercial 
insecticide  such  examination  or  analysis  of  the  sample  as  will  sub- 
stantially establish  the  conformity  or  non-conformity  of  the  said 
insecticide  to  the  guarantee  under  which  it  is  sold." 

This  nominal  fee  of  one  dollar  does  not  nearly  cover  the  actual 
cost  of  analysis  in  most  cases,  but  is  required  largely  as  a  guarantee 
of  good  faith  and  to  prevent  indiscriminate  sending  of  samples.  It 
seems  a  wise  provision  of  the  law  and  if  properly  used  by  the  growers 
throughout  the  state  would  materially  aid  them  in  obtaining  reliable 
materials  for  combating  their  insect  enemies,  as  well  as  in  aiding 
the  officials  charged  with  the  enforcement  of  the  law,  in  detecting 
fraudulent  materials  on  the  market. 

To  assist  in  carrying  out  the  provisions  of  this  part  of  the  law, 
the  following  rules  have  been  made,  and  consumers  are  requested  to 
submit  samples  for  analysis  in  accordance  therewith. 

RULES    AND    REGULATIONS 

1.  The  laboratory  will  not  usually  make  a  complete  analysis  of  a 
sample  but  only  such  "examination  or  analysis  as  will  substantially 
establish  the  conformity  or  non-conformity  of  the  said  insecticide  to 
the  guarantee  under  which  it  is  sold". 

2.  Analvsis  will  not  be  made  for  dealers. 


*  Statutes  of  California  of  1911,  Chap.  653,  Sec.  13. 


3.  All  samples  submitted  must  be  labelled  or  tagged  showing: 

1.  Name  of  sender. 

2.  Date  of  sampling. 

3.  Name  of  person  who  took  the  sample. 

4.  Manufacturer  or  guarantors  and  dealer. 

5.  Guarantee  under  Avhich  it  was  purchased. 

4.  When  a  sample  is  sent  for  analysis,  a  certificate  properly 
filled  out,  should  be  mailed  at  the  same  time,  together  with  the  fee 
of  one  dollar.  (A  blank  form  of  certificate  is  attached  to  this  cir- 
cular and  may  be  used.    Additional  copies  will  be  sent  on  application.) 

5.  Samples  should  never  be  placed  in  paper  bags.  Glass  is  always 
the  preferable  container,  although  an  air-tight  tin  can  may  be  used 
if  it  is  certain  that  the  substance  is  non-corrosive  and  dry. 

6.  The  container  should  always  be  scrupulously  clean  and  dry 
and  made  air  tight. 

7.  Bottles  containing  liquids  should  not  be  entirely  filled,  except 
in  the  case  of  lime-sulphur  solutions.  An  air  cushion  of  an  inch  or 
more  above  the  liquid  allows  for  the  expansion  of  the  contents  in  case 
of  unusual  heat  during  transit.  Stoppers  should  be  securely  fastened 
Corrosive  liquids  should  be  sent  in  glass  stoppered  bottles. 

8.  When  a  sample  is  received  for  analysis  which  appears  to  have 
been  improperly  taken  or  packed,  the  sample  will  not  be  analysed, 
and  the  fee  returned,  unless  a  new  lot  can  be  obtained. 

9.  Send  samples  by  parcel  post  or  by  express,  CHARGES  PRE- 
PAID TO, 

INSECTICIDE   LABORATORIES 

UNIVERSITY   OF   CALIFORNIA 

BERKELEY,    CAL. 


IMPORTANCE  OF  CAREFUL  SAMPLING 

Many  serious  disputes  and  misunderstandings  have  been  occa- 
sioned by  submitting  for  analysis  a  sample  which  did  not  truly 
represent  the  material  from  which  it  was  taken  on  account  of  care- 
lessness or  more  often  through  a  misunderstanding  of  the  principles 
involves.  The  sampling  of  the  material  is  no  less  important  than  a 
correct  analysis  and  should  never  be  done  in  a  haphazard  manner  nor 
trusted  to  anyone  not  thoroughly  responsible.  An  unfair  sample 
may  easily  cause  more  trouble  than  is  obvious  on  first  thought. 


Many  substances  deteriorate  very  rapidly  when  exposed  to  the 
air.  The  outer  portions  in  the  package  may  absorb  or  lose  moisture, 
oxidize,  or  lose  some  volatile  constituent,  or  in  some  way  change  in 
composition.  Common  examples  of  such  changes  are,  the  air  slaking 
of  lime,  the  absorption  of  water  by  lye,  and  the  decomposition  of 
cyanide  by  exposure  to  the  air.  It  is  evident  that  samples  taken  from 
different  parts  of  such  substances  would  differ  quite  materially  in 
composition  and  a  sample  from  a  newly  opened  package  would  be 
quite  different  from  one  taken  after  long  exposure  to  air  and  moisture. 
An  analysed  sample  from  such  material,  which  had  undergone  pro- 
longed exposure,  without  proper  mixing  will  be  of  no  value  whatever 
in  indicating  the  value  of  the  chemical  and  certainly  will  not  repre- 
sent the  contents  of  the  package  before  opening,  in  any  case.  Samples 
taken  under  such  conditions  may  involve  the  retailer,  the  jobber,  and 
the  manufacturer  in  unjust  suspicions,  of  adulteration,  or  of  dealing 
in  inferior  products.  The  integrity  or  the  ability  of  the  analyist  may 
also  be  questioned  when  in  reality  the  sampling  was  at  fault. 


METHODS    OF    SAMPLING 

Having  in  mind  these  general  remarks  about  the  importance  of 
careful  sampling,  the  following  suggestions  are  made,  with  the  hope 
that  they  will  be  of  use  in  sampling  insecticides. 

If  the  material  to  be  sampled  is  fine  grained,  or  a  liquid,  and  is 
of  uniform  composition  throughout,  no  special  caution  need  be 
observed,  except  that  it  should  be  thoroughly  mixed  and  a  portion 
taken  from  each  container.  These  portions  may  be  all  placed  together 
and  if  too  large  for  shipment  they  may  be  mixed  and  smaller  samples 
taken  out  for  analysis. 

If  the  material  is  a  liquid,  or  paste,  and  is  not  of  uniform  compo- 
sition throughout,  special  attention  should  be  given  to  the  mixing  and 
drawing  of  the  sample  before  the  heavier  portions  have  settled. 

If  the  material  is  in  lumps,  several  pieces  should  be  taken  from 
different  parts  of  each  package.  If  this  produces  a  sample  too  large, 
the  lumps  may  be  broken  into  smaller  pieces  and  thoroughly  mixed 
upon  a  clean  floor  or  table  and  divided  by  the  method  of  quartering 
as  follows :  The  material  is  spread  out  in  a  circular  flat  heap  and 
divided  into  quarters  and  the  two  diagonally  opposite  quarters 
removed.  The  two  remaining  quarters  are  again  thoroughly  mixed 
and  again  quartered  and  treated  as  before,  the  process  being  repeated 
until  a.  sample  is  obtained  of  the  desired  size. 


If  the  material  is  a  mixture  of  lumps  and  .fine  particles,  care  must 
be  exercised  to  remove  lumps  and  fine  particles  in  proportion  to  their 
abundance  in  the  material.  Large  samples  may  be  quartered  as  above 
after  breaking-  up  the  larger  pieces  in  each  quartering. 

Materials  which  appear  to  be  of  different  composition  in  different 
parts  of  the  package  should  be  entirely  removed  from  the  package 
and  mixed  before  sampling,  if  this  is  impracticable  without  removal. 

In  general  a  sample  should  not  be  sent  from  an  old  stock  of  goods 
except  for  the  purpose  of  determining  the  amount  of  deterioration  or 
some  such  purpose. 

INSECTICIDES    REQUIRING    EXTRA    CARE    IN    SAMPLING 

CYANIDS,  when  exposed  to  the  air  attract  moisture  and  change 
to  carbonates,  losing  a  large  percentage  of  cyanogen.  A  sample  for 
analysis  should  be  taken  from  a  freshly  opened  commercial  package 
and  there  should  be  several  pieces  from  each  package.  The  sample 
should  be  placed  in  dry  tin  or  glass  and  sealed  from  the  air.  The 
operation  of  sampling  should  be  performed  with  all  possible  haste 
as  the  attraction  of  moisture  and  decomposition  is  very  rapid.  The 
fine  residue  at  the  bottom  of  the  case  after  the  lumps  have  been  used 
should  never  be  submitted  as  representing  the  contents  of  the  original 
package. 

SAL-SODA  (Sodium  carbonate),  POTASSIUM  CARBONATE. 
These  substances  lose  or  gain  moisture  on  exposure  to  the  air  and 
change  to  the  less  alkaline  bi-carbonates.  A  thorough  mixing  is  neces- 
sary before  sampling.  Only  freshly  opened  packages  should  be 
sampled. 

CAUSTIC  SODA  AND  POTASH,  when  exposed  to  the  air  attract 
moisture  and  change  to  carbonates.  If  the  material  is  in  lumps,  the 
same  precautions  are  in  order  as  suggested  for  cyanids.  If  granu- 
lated, a  thorough  mixing  and  removal  of  a  portion  of  each  package 
will  suffice,  avoiding  any  unnecessary  exposure  since  the  absorption 
is  very  rapid. 

SULPHURIC  ACID,  rapidly  absorbs  moisture  from  the  air  in 
great  quantities.  The  sample  should  be  drawn  from  freshly  opened 
containers  and  immediately  placed  in  a  clean  dry  bottle,  provided 
with  tightly  fitting  ground  glass  stopper.  The  bottle  should  not  be 
entirely  filled.  The  stopper  should  be  tied  down  with  twine  and  the 
head  dipped  into  melted  parrafin,  sealing  wax  or  some  similar  material. 
Sawdust  is  probably  the  most  easily  obtainable  packing  for  the  bottle 
and  is  quite  satisfactory. 


LIME,  QUICKLIME,  HYDRATED  LIME.  Quicklime  (unslaked 
lime),  as  is  well  known,  decomposes  or  slakes  on  exposure  to  air  and 
very  soon  becomes  a  white  powder  called  air  slaked  lime.  This  powder 
is  a  mixture  of  hydrated  lime  and  carbonate  of  lime,  being  produced 
by  the  combined  action  of  the  moisture  and  carbon  dioxide  of  the 
air.  Pure  hydrated  lime  should  contain  no  carbonates  but  carbonates 
are  formed  very  soon  when  this  is  exposed  to  the  air.  Any  lime  should 
therefore  be  sampled  from  a  freshly  opened  package.  The  thorough 
mixing  of  the  material  before  sampling  or  the  removal  of  portions 
from  different  parts  of  the  package  are  necessary  in  sampling  these 
substances. 

LIME  SULFUR  solutions  deteriorate  very  rapidly  when  exposed 
to  the  air,  throwing  free  sulfur  out  of  solution  and  oxidizing  to  sul- 
fates. Samples  should  always  be  taken  from  freshly  opened  packages 
and  immediately  placed  in  clean  dry  bottles.  Cork  stoppers  will  do 
but  must  be  tied  down.  The  bottle  in  this  case  should  be  nearly  full 
to  lessen  the  oxidizing  influence  of  the  air. 

FORMALIN  (Formaldehyde),  loses  strength  very  rapidly  if  the 
package  is  left  open.  A  sample  should  be  an  original  package  if 
possible. 

POWDERED  DRUGS,  Pyrethrum,  Hellebore,  Tobacco,  Etc.  The 
insecticidal  value  of  many  such  compounds  is  lessened  on  exposure  to 
air  and  light.  Samples  therefore  should  be  taken  from  the  freshly 
opened  packages  only. 

SIZE    OF    SAMPLE 

As  a  rule  ONE  POUND  of  a  solid  or  ONE  QUART  of  a  liquid 
should  be  sent  as  a  sample.  In  case  of  expensive  materials  somewhat 
less  than  the  above  may  be  sent  if  the  substance  is  of  a  uniform  nature 
and  not  liable  to  deterioration. 

PACKING    SAMPLES 

Corrosive  substances  should  always  be  packed  in  some  absorbant 
material  such  as  sawdust.  It  is  more  important  to  have  the  packing 
firmly  pressed  around  the  package  to  prevent  shifting  than  to  have 
a  large  quantity  of  loose  packing.  Stoppers  and  covers  of  boxes 
should  be  securely  fastened. 


ADDEESSING 

Samples  and  letters  to  secure  prompt  attention  should  be  addressed 
as  follows: 


INSECTICIDE    LABORATORY 

UNIVERSITY   OF   CALIFORNIA 

BERKELEY,  CAL. 


[Note. — Certificate  on  opposite  page  may  be  filled  out,  and  mailed  to  above 
address.] 


DON'T  FAIL  TO  MAIL  CERTIFICATE  PROPERLY  FILLED 
OUT  AT  THE  SAME  TIME  THAT  THE  SAMPLE  IS  SENT,  WITH 
ENCLOSURE  OF  THE  FEE  OF  $1.00. 

CERTIFICATE 

Entitling  the  BONA  FIDE  USER  of  insecticide  material  in  the 
State  of  California  to  nominal  fees  for  the  examination  of  snch 
material. 

Insecticide  Laboratory, 

University  of  California, 
Berkeley,  Cal. 

This  is  to  certify  that  I  am  not  a  dealer  in,  nor  agent  for  the  sale 
of  any  insecticide  or  fungicide,  and  that  the  material,  a  sample  of 
which  I  have  sent  you  for  analysis,  was  purchased  by  me 

,  191 for  my  own  use  and  not  for  sale. 

The  material  is  said  to  contain  the  following  active  ingredients : 


and  inert  ingredients 

I  wish  it  analysed  or  examined  to  determine. 
The  Manufacturer,  Brand  and  Dealer  are 


I  enclose  the  analysis  fee  of  one  dollar. 

(Signature) 

(Address) 


(Date) 


